1. Field of the Invention
This invention lies in the broad category of those electrical switches known to the trade as AC general use snap switches. In a more particular sense, the invention falls in that category of AC switches normally wall-mounted within domestic or commercial buildings for use on alternating-current circuits for controlling resistive and inductive loads, tungsten-filament lamp loads, and motor loads.
2. Description of the Prior Art
It is very common to provide general purpose AC switches of the character described above, in which one or more elongated contact carrier arms of leaf spring characteristics, are deflected between circuit-closing and -opening positions, by a cam acting against the contact carrier responsive to rocking movement of the switch handle. Most usually, the switch handle is molded integrally with the cam, as for example in the U.S. Pat. No. 2,725,438 to Bentley. Accordingly, if it is found that a throw of perhaps 50 degrees total angular travel is needed for the cam movement, then the handle itself must obviously have the same amount of angular travel.
While this arrangement has been found entirely suitable and adequate when the switch handle is in the form of an elongated, radially outwardly projecting member, in recent years switches having so-called rocker handles have become very popular. A rocker handle, as typically provided in the industry, is most usually in the form of a flat, wide, elongated plate, lying almost flush with the wall plate generally associated with a switch of this type. The rocker handle, however, must desirably be limited to a total angular travel substantially less than that which is permissible and indeed favored for switch handles of the so-called toggle arm type.
Heretofore, it has been proposed to minimize angular travel of the rocker handle while still imparting a relatively long throw to the contact operating cam or equivalent thereof, by extending the contact operating means a substantial depth inwardly of the switch housing, from the axis of rocking movement of the handle. Typical examples of switches having elongated inwardly extending members disposed substantially radially of the axis of rocking movement of the handle, are found in various U.S. Pat. Nos. such as Carling 3,225,153; Sorenson 3,250,887; and Lewis 3,535,478.
It has been proposed, in some of these patents and also in other patents representative of the prior art, to interpose between the rocker handle and the contact carrier, a separate and distinct contact actuator. This is normally mounted for rocking movement about an axis separate from the axis of the rocker handle. The arrangement is typified by such U.S. Pat. Nos. as Mo Goto 3,315,052; the above mentioned Lewis Patent; Howe 3,670,121; and Taylor 2,794,890.
All of these prior art devices, however, have one or more deficiencies, the elimination of which is intended by the present invention. For example, in the prior art the construction is often extremely complicated, so as to be wholly incapable of widespread commercial use, particularly in so highly competitive a field as AC wall switches intended for domestic use. Or, in many instances the desired mechanical advantage resulting from a small angular travel of the rocker handle is not achieved. In other instances, assembly of the parts is complicated, by reason of the fact that the contact mechanism and the actuating means for said mechanism cannot be assembled except simultaneously with the rocker handle itself, an arrangement which is undesirable particularly when it is intended that the switch facilitates the replacement or rocker handles from time to time of decorative purposes.
In still other instances, the prior art has been noted as presenting difficulties in that to assure proper electrical characteristics in the switch, it is important that the switch function electrically without interfering with or being interfered with by the throw of the rocker handle by a user. In AC switches of this type, the most desirable electrical characteristic is to have a slow break and a fast make, and obviously, this must be carried out repetitively throughout the entire length of the switch without being affected by the way in which the rocker handle is thrown by a user. At the same time, it is important that the make or break action take place without imparting an undesirable click or bounce through the operating handle itself.